Direct interconnect gateway

ABSTRACT

A dedicated network gateway device that is capable of bridging, switching or routing network traffic between traditional network and direct interconnect networks, comprising: a first set of one or more traditional network ports with a single link per port generally comprising one or more of SFP+, QSFP, and QSFP+ connectors, such ports being connected to switches or devices that form a traditional network; and a second set of one or more direct interconnect ports with a high number of links per port (two or more) generally comprising one or more of MXC, MTP, and MTO connectors, such ports being connected to a direct interconnect network.

FIELD OF THE INVENTION

The present invention relates to I/O (Input/Output) traffic in a computer network. More specifically, the present invention relates to a dedicated device that bridges, switches or routes data between traditional networks and direct interconnect networks.

BACKGROUND OF THE INVENTION

Computer networks allow a multitude of nodes to route or otherwise exchange data with each other. As a result, computer networks are able to support an immense number of applications and services such as the shared use of storage servers, access to the World Wide Web, use of email, etc.

Nodes themselves can often be characterized into three types based on the specialized tasks that they perform: computation nodes, such as servers having CPUs that perform calculations (but that generally have little to no local disk space); I/O nodes that contain the system's secondary storage and provide parallel file-system services; and gateway nodes that provide connectivity to external data servers and mass storage systems. Some nodes can even serve more than one function, such as, for instance, handling both I/O and gateway functions.

I/O for parallel and distributed systems, however, has become a huge concern for both users and designers of computer systems. In this respect, while the speeds of CPUs have been increasing at an exponential rate virtually every year, the speed of I/O devices has unfortunately increased at a slower pace, often due to the fact that they can be more limited by the speed of mechanical components. I/O performance, a measure of I/O data traffic between nodes, is therefore often a limiting factor in network performance. Indeed, the mismatch in speed between CPUs and I/O is accentuated in parallel and distributed computer systems, leaving I/O as a bottleneck that can severely limit scalability. This is especially the case when the network is involved with commercial applications involving multimedia and scientific modelling, for instance, each of which has huge I/O requirements.

Direct interconnect networks, such as those disclosed in PCT Patent Application Publication No. WO 2015/027320 A1 (which describes a novel torus or higher radix interconnect topology for connecting network nodes in a mesh-like manner in parallel computer systems), generally restrict traffic to nodes that are part of the direct interconnect. While the novel system and architecture disclosed in PCT Patent Application Publication No. WO 2015/027320 A1 is particularly beneficial and practical for commercial deployment in data centers and cloud data centers, most data centers in operation today are still based, unfortunately, on a traditional legacy three-tier architecture, a fat tree architecture, or a DCell server-centric architecture, among others. With data centers based on these architectures, it is unfortunately either undesirable or impossible for them to join a direct interconnect, and they are therefore unable to exploit the benefits of such a network topology. Some prior art direct interconnect architectures have provided a system wherein each node, or a subset of nodes (i.e. gateway nodes), have dual connectivity, both to the direct interconnect and to the traditional network, but such nodes are difficult to manage and load the resources of the device as they bridge or route between the two networks.

It would therefore be desirable to have a direct interconnect gateway that is designed and capable of allowing direct interconnect devices and non-direct interconnect devices to communicate. Moreover, it would be beneficial to have a gateway that could assist in overcoming some of the shortcomings described above for I/O traffic.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides for a dedicated device, namely a gateway device, that is capable of bridging, switching or routing between traditional and direct interconnect networks.

In another aspect, the present invention provides a highly manageable gateway device that can be managed by network management systems.

In yet another aspect, the present invention provides a gateway device that allows for the coordination of MAC tables and ARP, broadcast, multicast and anycast responses between multiple direct interconnect ports.

In one embodiment, the present invention provides a dedicated network gateway device that is capable of bridging, switching or routing network traffic between traditional and direct interconnect networks, comprising: a first set of one or more traditional network ports with a single link per port, such ports being connected to switches or devices that form a traditional network; and a second set of one or more direct interconnect ports with two or more links per port, such ports being connected to a direct interconnect network. The traditional network ports may comprise one or more of SFP+, QSFP, and QSFP+ connectors, and may be connected to switch or router ports in the traditional network, while the direct interconnect ports may comprise one or more of MXC, MTP, and MTO connectors, and may be connected to a passive patch panel/hub used in the implementation of the direct interconnect network. Alternatively, the direct interconnect ports may be each connected to their own dedicated direct interconnect application-specific integrated circuit (ASIC), or they may each be connected to one or more shared application-specific integrated circuits (ASICs). The bridging, switching or routing function may be performed by a network switch ASIC or by a network controller ASIC. The ASICs may be capable of acting as a direct interconnect node with locally destined/sourced traffic sent over a traditional network interface line. In addition, in other embodiments, the direct interconnect ports may take the place of a device within the direct interconnect network, and they may even be connected to multiple direct interconnect networks.

In another embodiment, the present invention provides a dedicated network gateway device that is capable of bridging, switching or routing network traffic between traditional and direct interconnect networks, wherein said device comprises two ports, namely a first port that is a direct interconnect port that is capable of being connected to a direct interconnect network, and a second port that is a standard network port that is capable of being connected to switches or devices that form a traditional network. The first port may comprise one of a MXC, MTP, or MTO connector, and may be connected to a passive patch panel/hub used in the implementation of the direct interconnect network. The second port may comprise one of a SFP+, QSFP, or QSFP+ connector, and may be connected to switch or router ports in the traditional network.

In yet another embodiment, the present invention provides a dedicated network gateway device that is capable of bridging or routing network traffic between a traditional network and a direct interconnect network, comprising: a first set of traditional network ports with a single link per port, such ports being connected to end devices that form a first traditional network; and a second set of direct interconnect ports with two or more links per port, such ports being connected to the direct interconnect network, wherein said direct interconnect network acts as a backbone that allows network traffic to route from the dedicated network gateway device to another dedicated network gateway device, said another dedicated network gateway device comprising: a first set of traditional network ports with a single link per port, such ports being connected to end devices that form a second traditional network; and a second set of direct interconnect ports with two or more links per port, such ports being connected to the direct interconnect network.

In yet a further embodiment, the present invention provides a dedicated network gateway device that is capable of bridging, switching or routing network traffic between traditional network and direct interconnect networks, comprising: a first set of one or more traditional network ports with a single link per port, such ports being connected to switches or devices that form a traditional network; a second set of one or more direct interconnect ports with one or more links per port, such ports being connected to a direct interconnect network; and a plurality of direct interconnect ports that are logically associated to act as a single direct interconnect node.

In another embodiment, the present invention provides a computer-implemented method of bridging, switching or routing network traffic between a traditional network and a direct interconnect network, comprising the steps of: connecting the dedicated gateway device to the traditional network and the direct interconnect network, said dedicated gateway device acting as one or more nodes within the direct interconnect network; and forwarding the network traffic by means of the gateway device between the traditional network and the direct interconnect network based on headers or content of the network traffic.

In a further embodiment, the present invention provides a computer-implemented method of coordinating which gateway device should provide access to a resource located in a traditional network when said resource is accessible by more than one gateway device, comprising the steps of: (i) receiving an ARP, broadcast, multicast, or anycast traffic at a direct interconnect port, wherein said traffic is requesting access to the resource located in the traditional network, and wherein said direct interconnect port is linked via one or more hops to the more than one gateway devices, each of which is capable of providing access to the resource; (ii) calculating an optimum gateway device port out of the more than one gateway devices that should provide access to the resource; (iii) creating an association between the traffic, the direct interconnect node, and the calculated optimum gateway device port; and (iv) communicating the association with each of the more than one gateway devices to ensure that the calculated optimum gateway device port provides access to the resource. The step of calculating the optimum gateway device port that should provide access to the resource may comprise determining which of the more than one gateway device ports is closest to the direct interconnect port or may comprise employing a consensus algorithm to ensure consistency of the traffic. The step of communicating the association may be handled by a dedicated or shared coordination bus.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a high-level overview of a gateway device in accordance with one embodiment of the present invention.

FIG. 2 is an overview of a gateway device in accordance with one embodiment of the present invention, comprising a traditional network switch ASIC with certain ports connected to traditional network connectors and other ports connected to their own dedicated direct interconnect ASIC.

FIG. 2b is an overview of a gateway device in accordance with one embodiment of the present invention (related to that shown in FIG. 2), wherein each direct interconnect ASIC can be connected to more than one direct interconnect port, and can be connected to more than one traditional network switch ASIC port.

FIG. 2c is an overview of a gateway device in accordance with one embodiment of the present invention, comprising a single switch and direct interconnect ASIC that combines the functions of a traditional network switch ASIC and one or more direct interconnect ASICs.

FIG. 2d is an overview of a gateway device in accordance with one embodiment of the present invention, comprising a host interface card containing a traditional network port and a direct interconnect port.

FIG. 2e is an overview of a gateway device in accordance with one embodiment of the present invention, comprising a host interface card where the functions of a direct interconnect ASIC and traditional network controller ASIC are combined into a single direct interconnect and traditional ASIC.

FIG. 2f is an overview of a gateway device in accordance with one embodiment of the present invention, wherein the direct interconnect ports contain one or more links per port and are combined into groups by the gateway device, such that each group is logically associated by the gateway device to act as a single node within the direct interconnect network.

FIG. 3 is an overview of a gateway device in accordance with one embodiment of the present invention wherein direct interconnect ports are connected to a passive patch panel/hub.

FIG. 4 is an overview of a gateway device in accordance with one embodiment of the present invention wherein a direct interconnect port replaces a server within a direct interconnect topology.

FIG. 4b displays an embodiment as shown in FIG. 4, wherein the links of the direct interconnect ports are connected to different nodes.

FIG. 5 is an overview of one embodiment of the present invention wherein the direct interconnect ports on the gateway are linked to different direct interconnects to allow bridging, switching or routing between multiple direct interconnects.

FIG. 6 is an overview of one embodiment of the present invention wherein all or a majority of the nodes within the direct interconnect are composed of gateway ports, and wherein all or a majority of the other devices would be connected directly to one or more gateways.

FIG. 7 provides an example of how to minimize the average distance (in hops) from each device in the direct interconnect to the nearest gateway port.

FIG. 8 provides an example of how the gateway may coordinate which direct interconnect port should respond to an ARP request received at more than one port in the same direct interconnect.

FIG. 8b provides an example of an embodiment of a coordination mechanism (as per FIG. 8) wherein the coordination function is distributed across the direct interconnect ASICs and each direct interconnect ASIC is connected to a coordination bus used to communicate coordination information and decisions.

FIG. 9 provides one embodiment of a logic tree explaining how, when more than one gateway is connected to the same torus, the gateways may coordinate their knowledge of the torus topology and response to ARP, broadcast, multicast and anycast traffic.

FIG. 10 provides an example of how an intermediate gateway node may process a packet instead of routing the packet to another gateway node.

FIGS. 11 and 12 describe the operation of a preferred embodiment of a direct interconnect ASIC.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for a dedicated device, namely a gateway device, that is capable of bridging, switching or routing between traditional and direct interconnect networks. By employing such a dedicated device, the resources on the direct interconnect nodes do not have to be burdened by bridging, switching or routing between a direct interconnect and traditional network, thereby minimizing impacts on I/O performance. In addition, as opposed to the prior art use of gateway nodes, the present gateway device is a highly manageable device that can be managed by network management systems. Moreover, the gateway device of the present invention allows for the coordination of MAC tables and ARP, broadcast, multicast and anycast responses between multiple direct interconnect ports.

FIG. 1 shows a high-level overview of a gateway device 50 in accordance with one embodiment of the present invention, comprising two sets of ports. The first set of ports (in this example, the left-most twelve ports) are standard, traditional network ports 100 with a single link per port (e.g. SFP+, QSFP, QSFP+ connectors) that are connected to the existing switches and/or devices that form the traditional network. In a Clos topology (a multi-stage circuit switching network), for example, these ports 100 would most likely be connected to spine or super-spine ports. The second set of ports (the right-most twelve ports) are direct interconnect ports 102 with a high number of links (two or more) per port (e.g. with MXC/MTP/MTO connectors). If a passive patch panel/hub 60 similar to that disclosed in PCT Patent Application Publication No. WO 2015/027320 A1 is being used to support the direct interconnect topology, for example, then the direct interconnect ports 102 are connected to the passive patch panel/hub 60 (see FIG. 3). The gateway device 50 may be in the form of a 1 rack unit (RU) rack-mountable device, or even ½RU (or otherwise as desired) for efficient rack space savings. FIG. 2 shows an embodiment comprised of a traditional network switch application-specific integrated circuit (ASIC) 106, wherein the first set of traditional network ports 100 are each connected to traditional network connectors, and wherein the second set of direct interconnect ports 102 are each connected to their own dedicated direct interconnect ASIC 104. These dedicated direct interconnect ASICs 104 are preferably each capable of acting as a direct interconnect node with locally destined/sourced traffic sent over a traditional network interface line (e.g. 100 Gbps Ethernet). The connections between the ports of switch ASIC 106 and direct interconnect ASICs 104 can be implemented using any standard component interconnect such as 100GBase-KR4, 100GBase-KP4, 40GBase-KR4, 25GBase-KR, 10GBase-KR or any other similar standard.

Traditional network switch ASIC 106 contains standard network traffic forwarding functionality, including learning the devices reachable through its ports, sending received traffic through the appropriate egress port, network filtering, traffic inspection and other functionality typically found in layer 2, layer 3 and layer 4 and above network switches, routers and bridges. Forwarding decisions may be based on one or more factors, including but not limited to source and destination layer 2 (MAC) addresses, source port, source and destination layer 3 (IPv4, IPv6, etc.) addresses, source and destination layer 4 ports, and layer 5 and above headers and data payloads.

Network traffic received from the direct interconnect at a direct interconnect ASIC 104 that has an ultimate destination that is reachable through the standard ports of switch ASIC 106 will be sent from direct interconnect ASIC 104 to switch ASIC 106 where switch ASIC 106 standard traffic forwarding functionality will transmit the traffic through the appropriate standard port.

Similarly, network traffic received by switch ASIC 106 from a standard port that has an ultimate destination that is reachable through a direct interconnect ASIC 104 will be forwarded by switch ASIC 106 to direct interconnect ASIC 104.

In another embodiment (not shown), and as applicable for every possible embodiment, it would be understood that switch ASIC 106 (and all similar ASICs discussed herein) may be replaced by a field-programmable gate array (FPGA), general purpose processor, network processor or any other device capable of performing network traffic forwarding.

In another embodiment (not shown), and as applicable for every possible embodiment, it would be understood that direct interconnect ASIC 104 (and all similar ASICs discussed herein) may be replaced by a field-programmable gate array (FPGA), general purpose processor, network processor or any other device capable of acting as a node in a direct interconnect network.

FIG. 2b shows another embodiment where each direct interconnect ASIC 104 can be connected to one or more direct interconnect ports 102 and can be connected to one or more traditional network switch ASIC 106 ports.

FIG. 2c shows another embodiment where a single switch and direct interconnect ASIC 105 combines the functions of the traditional network switch ASIC 106 and one or more direct interconnect ASICs 104. Once again, it would be understood that single switch and direct interconnect ASIC 105 (and all similar ASICs discussed herein) may be replaced by a field-programmable gate array (FPGA), general purpose processor, network processor or any other device capable of performing network traffic forwarding and/or acting as a node in a direct interconnect network.

FIG. 2d shows another embodiment of a gateway device in the form of a host interface card 110 containing a traditional network port and direct interconnect port. Host interface card 110 is designed to be connected to a host device via a communication bus such as PCIe, Gen-Z or CCIX. The host device could be a server, computer, hard drive, solid state drive, drive cabinet or any other device capable of sending and receiving data. The traditional network port is connected to standard network controller ASIC 108 (or similarly a field-programmable gate array (FPGA), general purpose processor, network processor or any other device capable of performing network traffic forwarding, etc.) and the direct interconnect port is connected to direct interconnect ASIC 104. Direct interconnect ASIC 104 is also connected to network controller ASIC 108. In this form, network controller ASIC 108 would be capable of switching traffic between the traditional network and direct interconnect network without intervention by the host.

FIG. 2e shows an embodiment of another host interface card 111 where the functions of the direct interconnect ASIC 104 and network control ASIC 108 are combined into a single direct interconnect and traditional ASIC 107. Once again, it would be understood that single direct interconnect and traditional ASIC 107 (and all similar ASICs discussed herein) may be replaced by a field-programmable gate array (FPGA), general purpose processor, network processor or any other device capable of performing network traffic forwarding and/or acting as a node in a direct interconnect network.

FIG. 2f shows another embodiment where the direct interconnect ports 102 contain one or more links per port and are combined into groups 55 by the gateway device 50. Each group 55 is logically associated by the gateway device 50 to act as a single node within the direct interconnect network.

As shown in FIG. 4, the direct interconnect ports 102 and groups 55 would each take the place of a device within the direct interconnect topology.

In yet another embodiment, if a passive patch panel/hub 60 is not utilized in the direct interconnect, then the individual links of each gateway port (i.e. the direct interconnect ports 102) may be connected to devices that are part of the direct interconnect. In this respect, FIG. 4b shows an embodiment wherein the links of one of the direct interconnect ports 102 are individually connected to neighbor nodes within the direct interconnect network. In FIG. 4b , the direct interconnect takes the form of a two-dimensional torus and the 4 links that comprise the direct interconnect port 102 are numbered 1, 2, 3 and 4. In order to form the two-dimensional torus, link 1 is connected to device A, link 2 is connected to device B, link 3 is connected to device C and link 4 is connected to device D. Similarly, for other topologies, each link of the direct interconnect port 102 should be connected to the appropriate neighbor device required by that topology.

In a further embodiment, as shown in FIG. 5, the gateway device 50 could also be used to bridge, switch or route between multiple direct interconnects. In this case, the direct interconnect ports 102 on the gateway device 50 will be divided between the different direct interconnects (shown in FIG. 5 as A and B). All of the devices in direct interconnect A would then be reachable from direct interconnect A through the gateway device 50 and vice versa. In the example provided, traffic from a device in Direct Interconnect A destined for a device in Direct Interconnect B would first traverse Direct Interconnect A to the direct interconnect port 102 shown as A4 on gateway device 50. Gateway device 50 would then forward this traffic through the direct interconnect port 102 shown as B2 where it would then be forwarded through Direct Interconnect B to the destination node.

In yet another embodiment of the present invention, the gateways could be used as access switches and the direct interconnect would form the backbone (see FIG. 6). In this case, all or the majority of the nodes within the direct interconnect would be composed of gateway ports, and all or the majority of the other devices would be connected directly to the traditional network ports 100 of gateway device 50. In the example provided in FIG. 6, traffic from Device group A destined for Device group B would first be forward to gateway device 50A. The gateway 50A forwarding function would recognize that the destination device is reachable through the direct interconnect and would forward the traffic through one of gateway device 50A′s direct interconnect ports 102. The direct interconnect would then forward the traffic to one of the direct interconnect ports of gateway device 50B. The gateway 50B forwarding function would recognize that the destination device is reachable through one of its standard network ports and would forward the traffic appropriately.

In order to maximize I/O traffic efficiencies, FIG. 7 provides an example of how, in a single direct interconnect deployment, the direct interconnect ports 102 could be chosen to minimize the average distance (number of hops) from each gateway device 50 in the direct interconnect to the nearest gateway port. In a 4×4 2D torus with the nodes numbered as per FIG. 7, having the gateway act as nodes 1, 6, 11 and 16 would minimize the distance to the other nodes in the direct interconnect. However, a person skilled in the art would also understand that if a subset of the nodes tends to generate a higher amount of I/O than the average, then the deployment of the gateway nodes could be biased to be closer to these higher I/O nodes. Multiple algorithms are known that can be used to determine the optimum location for these I/O nodes (see, for instance, Bae, M., Bose, B.: “Resource Placement in Torus-Based Networks” in: Proc. IEEE International Parallel Processing Symposium, pp. 327-331. IEEE Computer Society Press, Los Alamitos (1996); Dillow, David A. et al.: “I/O Congestion Avoidance via Routing and Object Placement” United States: N. p., 2011. Print. Proceedings of the Cray User Group conference (CUG 2011). Fairbanks, Ak., USA; Almohammad, B., Bose, B.: “Resource Placements in 2D Tori” in: Proc. IPPS 1998 Proceedings of the 12th International Parallel Processing Symposium on International Parallel Processing Symposium, p. 431. IEEE Computer Society, Washington, D.C. (1998); Dillow, David A. et al.: “Enhancing I/O Throughput via Efficient Routing and Placement for Large-scale Parallel File Systems” in: Conference Proceedings of the IEEE International Performance, Computing, and Communications Conference (IPCCC), 2011 IEEE 30th International; Ezell, M. et al.: “I/O Router Placement and Fine-Grained Routing on Titan to Support Spider II” in: Proceedings of the Cray User Group Conference (CUG), May 2014; and Babatunde, A. et al.: “I/O Node Placement for Performance and Reliability in Torus Networks”, Department of Computer Science, Texas A&M University, January 2006).

In a preferred embodiment, the direct interconnect ports 102 will act as standard direct interconnect ports and autonomously forward traffic remaining in the direct interconnect (i.e. forwarding FLITs). They will also recombine FLITs into network packets for traffic destined for devices not in the direct interconnect (see PCT Patent Application Publication No. WO 2015/120539 A1 for an optimal method to route packets in a distributed direct interconnect network). The gateway device 50 should preferably also have the capability to transmit/receive network packets to/from each of the traditional network ports 100 and direct interconnect ports 102, and also be able to interpret and forward this traffic based on layer 2, 3 or as per the above.

In a preferred embodiment, standard northbound network management interfaces would be exposed (e.g. CLI, OpenFlow, SNMP, REST, etc.) to allow a network management system to manage the gateway device 50.

In one embodiment, when multiple gateway ports are connected to the same direct interconnect, all packets from a given flow should preferably egress on the same gateway port to aid in guaranteeing in-order packet delivery.

The gateway device 50 should preferably be configured to aggregate MAC forwarding tables between the direct interconnect ports 102 connected to the same direct interconnect (i.e. when a direct interconnect port learns of a VLAN/MAC address/node_id tuple, this tuple should preferably be shared with the other direct interconnect ports 102 connected to the same direct interconnect).

In a preferred embodiment, when an ARP request is received at one or more of the direct interconnect ports 102 connected to the same direct interconnect, the decision of which direct interconnect port should respond should be coordinated by the gateway 50 to ensure only a single response is transmitted (see e.g. at FIG. 8). This could be done, for example, by choosing the direct interconnect port closest to the source of the ARP request, the first direct interconnect port to receive the ARP, through a round-robin selection scheme, through a hash of some portion of the ARP request (IP address, source MAC, etc.), or another algorithm known to persons skilled in the art. FIG. 8b shows one embodiment of this coordination mechanism wherein the coordination function is distributed across the direct interconnect ASICs 104 and each direct interconnect ASIC 104 is connected to coordination bus 112 used to communicate coordination information and decisions. In another embodiment, this coordination function may be centralized in a dedicated coordination ASIC and each direct interconnect ASIC 104 is connected to the coordination ASIC via a dedicated or shared coordination bus 112.

When more than one gateway is connected to the same torus, the gateway devices 50 should preferably coordinate their knowledge of the torus topology and response to ARP requests in a similar fashion to the single gateway case discussed above (see FIG. 9 for a logic tree re such coordination). In one embodiment, the gateways could discover each other through a broadcast protocol. In another embodiment, the gateways could be configured to know the location of the other gateways. In yet another embodiment, a consensus algorithm such as Raft could be used to ensure coordination of the gateways and consistency of the traffic—gateway/port associations (see e.g. Ongaro, D., Ousterhout, J.: “In Search of an Understandable Consensus Algorithm (Extended Version)” in: 2014 USENIX Annual Technical Conference, Jun. 19, 2014, Philadelphia, Pa.; Woos, D. et al.: “Planning for Change in a Formal Verification of the Raft Consensus Protocol” in: Certified Programs and Proofs (CPP), January 2016).

In general, whenever a torus node would like to communicate with a resource that is accessible through one or more gateway devices 50, the gateway(s) should preferably coordinate which gateway port is chosen to provide access to that resource in a similar manner to the ARP example described above. Examples of this include anycast, broadcast and multicast traffic, node and service discovery protocols and IPv6 neighbor discovery.

As a further consideration, it is important to note that, in many cases, non-minimal routing is used within a direct interconnect. Since the gateway(s) within a direct interconnect have gateway ports in multiple locations within the topology, it is possible for traffic destined for one gateway port to traverse one of the other gateway ports first. It would therefore be preferable to increase efficiencies by having a single, first gateway port process the traffic instead of allowing the traffic to traverse to a more distant gateway port. An example of this is provided in FIG. 10, where node 5 is sending traffic to node 1, but due to non-minimal routing, the packet will traverse node 6. In one embodiment, to improve efficiencies, the gateway with the port located at node 6 will recognize that the packet is destined for another gateway port and will process the packet as if it is destined for node 6 instead of forwarding it through the direct interconnect via node 2.

As noted above, the Direct Interconnect ASIC 104 provides connectivity between Switch ASIC 106 and a direct interconnect. In order to ensure that a person skilled in the art would be able to make and work a network gateway device of the present invention, FIGS. 11 and 12 describe the operation of a preferred embodiment of Direct Interconnect ASIC 104. This operation is also applicable, with any modifications as necessary, for other ASICs within the scope of this invention, including ASICs 105, 107 and 108, as appropriate.

As is well-known in the art, Switch ASIC 106 transmits and receives Ethernet frames. FIG. 11 describes how Ethernet Frame 200, generated by Switch ASIC 106, is processed by Direct Interconnect ASIC 104. MAC Address Database 201 contains a list of Ethernet MAC addresses and the direct interconnect nodes associated with each Ethernet MAC address. The Ethernet Frame 200 received from Switch ASIC 106 is examined and the Source and Destination MAC addresses are retrieved from its header. These MAC Addresses are used as indices to MAC Address Database 201. The source MAC address of the Ethernet Frame 301 is combined with the node number of the current to create or update an association between this node number and source MAC address in MAC Address Database 201.

If the Destination MAC address of Ethernet Frame 200 is in MAC Address Database 201, then the Node Number 202 associated with this MAC Address is retrieved from Mac Address Database 201. The Node Number 202 is then used as an index into Source Route Database 206 and source route 203 associated with Node Number 202 is retrieved from the Source Route Database 206. As is well-known in the art, source route databases contain a list of network destinations and one or more paths through the network to reach each destination. A source route database may be manually populated or may rely on well-known automated topology discovery and route computation algorithms. Ethernet Frame 200 is then converted into FLITs 204. A FLIT is a specialized frame type used in direct interconnects and can be of either fixed or variable size. In a preferred embodiment, FLITs will be of a fixed size. In another embodiment, FLITs will be of a variable size within a minimum and maximum size. In yet another embodiment, FLITs will be sized so that the Ethernet Frame 200 exactly fits into the FLIT payload.

If the Ethernet Frame 200 is larger than the payload of a single FLIT, multiple FLITs 204 will be created. If the Ethernet Frame 200 fits into the payload of a single FLIT, then a single FLIT will be created. Source Route 203 is then inserted into the header of the first of the FLITs 204 along with the node number of the current node. FLITs 204 are then transmitted from the Egress Port 205 specified in Source Route 203.

If the Destination MAC address of Ethernet Frame 200 is not in MAC Address Database 201 or if the Destination MAC Address of Ethernet Frame 200 indicates that it is a broadcast Ethernet packet, then Ethernet Frame 200 is converted into FLITs 204 as in the case described above although a source route will not be included. Once FLITs 204 have been created, a flag in the header of the first FLIT is set to indicate that these FLITs should be broadcast to every node in the direct interconnect. A time-to-live (TTL) value is also set in the header of the first FLIT. The TTL determines the maximum number of times broadcast FLITs can be forwarded through the direct interconnect. In one embodiment, anycast and multicast Ethernet frames are treated as if they are broadcast frames, as above.

FIG. 12 describes how FLITs 204 are processed by Direct Interconnect ASIC 104 in a preferred embodiment of Direct Interconnect ASIC 104. FLITs 204 from Direct Interconnect 301 are received by Direct Interconnect ASIC 104 and the header of the first of these FLITs is examined to see if the broadcast flag is set. If the broadcast flag is not set, Source Route 203 is retrieved from the first FLIT and it is determined whether the source route indicates that the current node is the destination node for the FLITs 204. In another embodiment, the FLITs contain the node number of the destination node and it is the node number that is used to determine if the current node is the destination node for the FLITs 204. If the current node is the destination node for the FLITs 204, the FLITs 204 are combined to form Ethernet Frame 301. The source MAC address of the Ethernet Frame 301 is combined with the node number in the header of the first FLIT to create or update an association between said node number and source MAC address in MAC Address Database 201. Ethernet frame 301 is then transmitted to Switch ASIC 106.

If it is determined that this is not the destination node, the source route is used to determine the egress port 302 for FLITs 204. FLITs 204 are then transmitted out the egress port 302.

If the broadcast flag is set in the first FLIT header, the FLITs 204 are combined to form Ethernet Frame 301. The source MAC address of the Ethernet Frame 301 is combined with the node number in the header of the first FLIT to create or update an association between said node number and source MAC address in MAC Address Database 301. Ethernet Frame 301 is transmitted to Switch ASIC 106.

The TTL in the header of the first FLIT is then decremented by one. If the TTL is now equal to zero, then FLITs 204 are discarded. If the TTL is greater than zero, the FLITs 204 are transmitted out all egress ports except for the ingress port from which FLITs 204 were originally received.

In other embodiments of Direct Interconnect ASIC 104, source routing may not be used. In one embodiment, the destination MAC address of Ethernet Frame 200 will be used by each node to perform a local next-hop route lookup. In another embodiment, destination node information in the FLIT header will be used by each node to perform a local next-hop route lookup.

It will be obvious to those well-versed in the art that other embodiments of Direct Interconnect 104 and Switch ASIC 106 may be designed to work with protocols other than Ethernet. In one embodiment, these elements will be designed to work with Gen-Z. In this case, Direct Interconnect 104 would expect to received Gen-Z Core64 packets instead of Ethernet frames. Instead of Ethernet MAC addresses, Gen-Z GCIDs (Global Component IDs) would be used and associated with direct interconnect node numbers.

Although specific embodiments of the invention have been described, it will be apparent to one skilled in the art that variations and modifications to the embodiments may be made within the scope of the following claims. 

We claim:
 1. A dedicated network gateway device that is capable of bridging, switching or routing network traffic between traditional and direct interconnect networks, comprising: a first set of at least one traditional network ports with a single link per port, said first set of at least one traditional network ports comprising at least one of small form-factor pluggable (SFP+), quad small form factor pluggable (QSFP), and quad small form factor pluggable (QSFP+) connectors that are connected to one of switches and devices that form the traditional network; and a second set of at least one direct interconnect ports with at least two links per port, said second set of at least one direct interconnect ports comprising at least one of micro coaxial connector (MXC), multi-fiber termination push-on (MTP), and multi-fiber push on (MTO) connectors that are connected to the direct interconnect network; and wherein the first set of at least one traditional network ports and the second set of at least one direct interconnect ports together provide a means by which the dedicated network gateway device is capable of bridging, switching or routing network traffic between the traditional network and the direct interconnect network; and wherein the gateway device further comprises a coordination function that assigns one or more direct interconnect nodes within the direct interconnect network to each of the at least one direct interconnect ports so only one of the at least one direct interconnect ports processes the network traffic for a given flow.
 2. The device of claim 1 wherein at least one traditional network port is connected to at least one of a switch port and router port in the traditional network.
 3. The device of claim 1 wherein the first set of at least one traditional network ports are each connected to the traditional network via at least a traditional network switch application-specific integrated circuit (ASIC), network controller ASIC, field-programmable gate array (FPGA), general purpose processor, network processor, or other device that is capable of performing network traffic forwarding functionality.
 4. The device of claim 1 wherein the second set of at least one direct interconnect ports are each connected to the direct interconnect network via at least a dedicated direct interconnect application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), general purpose processor, network processor, or other device that is capable of performing network traffic forwarding functionality.
 5. The device of claim 4 wherein the other device is a passive patch panel/hub used in the implementation of the direct interconnect network.
 6. The device of claim 4 wherein at least one of the application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), general purpose processors, network processors, and other devices are capable of acting as a direct interconnect node with locally destined/sourced traffic sent over a traditional network interface line.
 7. The device of claim 1 wherein the second set of at least one direct interconnect ports take the place of a device within the direct interconnect network.
 8. The device of claim 1 wherein the second set of at least one direct interconnect ports are connected to multiple direct interconnect networks.
 9. A computer-implemented method of at least one of bridging, switching and routing network traffic between a traditional network and a direct interconnect network, comprising the steps of: connecting a dedicated gateway device to the traditional network and the direct interconnect network, said dedicated gateway device acting as one or more nodes within the direct interconnect network; and forwarding the network traffic by means of the gateway device between the traditional network and the direct interconnect network based on headers or content of the network traffic; wherein the dedicated gateway device comprises: a first set of at least one traditional network ports with a single link per port, said first set of at least one traditional network ports comprising at least one of small form-factor pluggable (SFP+), quad small form factor pluggable (QSFP), and quad small form factor pluggable (QSFP+) connectors that are connected to one of switches and devices that form the traditional network, and a second set of at least one direct interconnect ports with at least two links per port, said second set of at least one direct interconnect ports comprising at least one of micro coaxial connector (MXC), multi-fiber termination push-on (MTP), and multi-fiber push on (MTO) connectors that are connected to the direct interconnect network, wherein the first set and second set of ports together provide a means by which the dedicated network gateway device is capable of bridging, switching or routing network traffic between the traditional network and the direct interconnect network, and wherein the gateway device further comprises a coordination function that assigns one or more direct interconnect nodes within the direct interconnect network to each of the at least one direct interconnect ports so only one of the at least one direct interconnect ports processes the network traffic for a given flow.
 10. A computer-implemented method of coordinating access to a resource located in a traditional network when said resource is accessible by more than one gateway device, the method comprising the steps of: receiving an ARP, broadcast, multicast, or anycast traffic at a direct interconnect port, wherein said traffic is requesting access to the resource located in the traditional network, and wherein said direct interconnect port is linked via one or more hops to the more than one gateway device, each of which is capable of providing access to the resource; calculating an optimum gateway device port out of the more than one gateway device that should provide access to the resource; creating an association between the traffic, the direct interconnect node, and the calculated optimum gateway device port; and communicating the association with each of the more than one gateway device to ensure that the calculated optimum gateway device port provides access to the resource; wherein the dedicated gateway device comprises: a first set of at least one traditional network ports with a single link per port, said first set of at least one traditional network ports comprising at least one of small form-factor pluggable (SFP+), quad small form factor pluggable (QSFP), and quad small form factor pluggable (QSFP+) connectors that are connected to one of switches and devices that form the traditional network, and a second set of at least one direct interconnect ports with at least two links per port, said second set of at least one direct interconnect ports comprising at least one of micro coaxial connector (MXC), multi-fiber termination push-on (MTP), and multi-fiber push on (MTO) connectors that are connected to the direct interconnect network, wherein the first set and second set of ports together provide a means by which the dedicated network gateway device is capable of bridging, switching or routing network traffic between the traditional network and the direct interconnect network, and wherein the gateway device further comprises a coordination function that assigns one or more direct interconnect nodes within the direct interconnect network to each of the at least one direct interconnect ports so only one of the at least one direct interconnect ports processes the network traffic for a given flow.
 11. The computer-implemented method of claim 10, wherein the step of calculating the optimum gateway device port that should provide access to the resource comprises determining which of the more than one gateway device ports is closest to the direct interconnect port.
 12. The computer-implemented method of claim 10, wherein the step of calculating the optimum gateway device port that should provide access to the resource comprises employing a consensus algorithm to ensure consistency of the traffic.
 13. The computer-implemented method of claim 10, wherein the step of communicating the association is handled by a dedicated or shared coordination bus. 